This is just an endcap for the left upright makerslide. My X and Y motor wiring will run up the centre of this extrusion hence the channel at back. Will allow lcd controller case to be glued to top like this one http://www.thingiverse.com/thing:29081. have included the sketchup file if you want to mirror for the leftprint and bolt into top of your hadron Z makerslides. Have not printed or tested, nut traps may require some work, 6mm M3 button head screw should work to retain cap